Abstract: The extensively used digital elevation model (DEM) data make it possible to reconstruct the paleosurface. In this paper, take the Guide basin for example, several methods for extracting the data of surface exposure samples representing the paleosurface have been analyzed and compared. The authors propose an optimal method, i.e. the top point representing the original sedimentary strata in the outcrops should be selected as the interpolated sample. They extracted the sample data of the top of the Pleistocene surface outcrop. Based on an analysis of the sample characters and a comparison of the interpolated values, the natural neighbor interpolation has been adopted to reconstruct the Pleistocene paleosurface of the study area. The error of the reconstructed paleosurface has been decreased by using the proper interpolation to the properly selected samples. The extraction of correct sample points plus the selection of the proper interpolation have optimized the reconstruction of the paleosurface.